Preparation of bis (2-cyanoacrylate)monomers

ABSTRACT

Difunctional monomers of the formula, ##EQU1## where R is an organic linking group derived from a diol or a dihalide of the formula X-R-X, where X is either chlorine, bromine, iodine, or hydroxy, are prepared by reacting a conjugated diene, exemplified by anthracene, with an ester of 2-cyanoacrylic acid to form the Diels-Alder adduct of the ester. The ester adduct is hydrolyzed to ultimately obtain either the Diels-Alder adduct of either 2-cyanoacrylic acid--alkali metal salt or 2-cyanoacryloyl halide. These latter intermediates are respectively reacted with either the dihalide or the diol to afford the bis-Diels-Alder adduct of the R substituted bis (2-cyanoacrylate) monomer. The protective diene group may then be removed, for example, by reaction with excess maleic anhydride and the resulting difunctional monomer isolated. 
     The difunctional monomers thus prepared can be utilized as crosslinking agents in blends comprising one or more of these difunctional monomers and at least one monofunctional monomer, exemplified by an ester of 2-cyanoacrylic acid. Alternately, one or more difunctional monomers can be homopolymerized or copolymerized to a highly crosslinked polymer. The copolymerized compositions of the monomer blends are particularly useful as adhesives, especially in dental applications for coating or sealing enamel surfaces of teeth to allay decay, or for the bonding of brackets to teeth in orthodontics the bond being substantially more resistant to moisture than where the monofunctional monomer is used alone.

This application is a continuation-in-part of copending applicationsSer. No. 308,375 filed Nov. 21, 1972, and Ser. No. 308,376, filed Nov.21, 1972, both now abandoned.

DISCLOSURE OF THE INVENTION

1. Field of the Invention

This invention relates to new and novel compositions and to methods forpreparing the same. In particular, this invention relates to methods forpreparing new bis esters represented by ##EQU2## of the following "FlowChart" AND ##EQU3## where R is an organo linking group and D is ablocking group derived from a cyclic 1,3 diene. The monomers representedby formula I prepared by this process have been found to be particularlyuseful as adhesives, especially in dental applications when incorporatedas crosslinking agents for esters of 2-cyanoacrylic acid. The bis estersrepresented by Formula V are particularly useful in the preparation ofmonomers of Formula VI.

2. Description of the Prior Art

The production of esters of 2-cyanoacrylic acid via in situ formation ofthe Diels-Alder anthracene adducts of 2-cyanoacrylic acid esters isdescribed in U.S. Pat. No. 3,463,804. This patent, however, is concernedonly with the preparation of the monofunctional monomers, such as theesters of 2-cyanoacrylic acid, and makes no reference to any means forobtaining a difunctional bis (2-cyanoacrylate) ester, such as of thisinvention, which can be polymerized alone, or in admixture with other2-cyanoacrylate esters or bis (2-cyanoacrylate) esters, to affordcrosslinked polymeric compositions. Japanese Patent 46-5135 (1971)discloses a similar process and likewise makes no reference to bis(2-cyanoacrylate) monomers.

U.S. Pat. No. 3,142,698 purports to disclose a method of preparingvarious difunctional monomers, including some of this invention. Themethod disclosed in U.S. Pat. No. 3,142,698 entails the preparaton of analkylene glycol dicyanoacetate from an alkylene glycol and cyanoaceticacid. The alkylene glycol dicyanoacetate is then condensed withformaldehyde to allegedly produce the alkylene glycol bis(2-cyanoacrylate). All attempts to produce such difunctional monomers inaccordance with the teachings of that disclosure have proven completelyunsuccessful. The products obtained are polymeric and, unlike thedifunctional monomers of this invention, are insoluble in most commonorganic solvents such as chloroform, benzene, acetone, and the like.Infrared analysis (IR) of the resinous product confirmed the absence ofany monomer having the alleged structure and, instead, showed a producthaving strong residual hydroxyl group absorptions. The IR data, coupledwith the insolubility of the product, suggests that the formaldehyde hasreacted with the alkylene glycol dicyanoacetate in an adverse manner soas to give a highly crosslinked polymeric composition instead of thealleged monomeric structures.

Efforts to develop difunctional monomers bearing the highly reactivecyanoacrylate functional group and which can be employed as acrosslinking agent with other monofunctional monomers that polymerizethrough a vinyl bond, particularly the cyanoacrylates, have heretoforebeen without actual success.

Therefore, the primary object of this invention is to provide a methodfor preparing bis (2-cyanoacrylate) monomers and to provide compoundsthat can readly be converted to bis (2-cyanoacrylate) monomers so thatthe same can be employed as crosslinking agents, particularly formonofunctional esters of 2-cyanoacrylic acid.

A further object of this invention is to provide crosslinkable adhesivecompositions comprising 2-cyanoacrylate esters and difunctional bis(2-cyanoacrylate) monomers which, upon copolymerization form acrosslinked polymer having improved resistance to moisture and improvedadhesive and cohesive bond strength over that obtainable through the useof the cyanoacrylate ester alone.

Another object of this invention is to provide compositions forperforming dental prophylaxis, for preparing dental restorations, or forbonding dental devices to teeth, such compositions having improvedadhesion to tooth structure as well as improved strength properties.

It is a still further object of this invention to provide a compositionfor use as a pit and fissure sealant that has improved adhesive andcohesive strength to enable it to better withstand the grinding forceswhich teeth undergo.

SUMMARY OF THE INVENTION

These and other objects and advantages are achieved by preparing the bis(2-cyanoacrylate) monomers of this invention in accordance with thegeneral reaction scheme set forth below. In this scheme the active vinylgroup, ##EQU4## of a 2-cyanoacrylate ester (Formula I of Flow Chart) isfirst blocked by adding a blocking group, designated by ##SPC1##

through a conventional Diels-Alder rection which blocking group ismaintained until the bis acrylate is formed. The blocking group ##SPC2##

is then removed, restoring the active vinyl groups of the bis2-cyanoacrylate. This is illustrated in the following Flow Chart towhich reference is now made. Referring to the following Flow Chart, anester of 2-cyanoacrylic acid of General Formula I is reacted with acyclic 1,3-diene to form a Diels-Alder adduct represented by GeneralFormula (II). Typically, where anthracene is employed as the 1,3 dieneand isobutyl 2-cyanoacrylate as the ester of Formula I, the Diels-Alderadduct of Formula II would be 11-cyano-11-carboisobutoxy-9,10-dihydro-9,10-endoethanoanthracene represented as ##SPC3##

The adduct of General Formula II in which ##SPC4##

is the anthracene blocking group is then subjected to alkalinehydrolysis followed by acidification to form the corresponding2-cyanoacrylic acid adduct represented by Formula III. Treatment withalkali forms the alkali metal salt represented by Formula (IV-A).Alternatively, the 2-cyanoacrylic acid adduct of Formula (III) can besuitably converted to the 2-cyanoacryloyl halide adduct represented bythe Formula (IV-B).

The metal salt of the 2-cyanoacrylic acid adduct of Formula (IV-A) isthen reacted with a dihalide, X-R-X, where X is independently bromide,iodine, or chlorine in one approach or, in the other aproach, the2-cyanoacryloyl halide adduct of Formula (IV-B) is reacted with a diolof the Formula, HO-R-OH. R, in each case is an organo linking groupdefined in more detail below. Either of these routes result in theformation of the bis-Diels-Alder adduct represented by Formula (V). Thisbis-Diels-Alder adduct may then be converted into its corresponding bis(2-cyanoacrylate) monomer, as represented by Formula (VI) by heating theadduct in the presence of excess maleic anhydride. In this reactionscheme, ##SPC5##

represents the cyclic 1,3-diene blocking group inserted in the firststep of the sequence via Diels-Alder adduct formation.

                  FLOW CHART                                                      ______________________________________                                        CN                 CH.sub.2                                                   | D                   1) KOH/EtOH/H.sub.2 O                          CH.sub.2 =C--COOR'                                                                       →                                                                              D| →                                                          CN          2) HCl                                                            C∠                                                                      COOR'                                                                         II                                                                       CH.sub.2                                                                      D|                                                                   C--COOM.sup.+                                                                 |X--R--X                                               M             CN                                                              CH.sub.2      IV-A                                                            D|                                                                   C--COOH                                                                       |                                                                    CN                                                                                          CH.sub.2 HO--R--OH                                                            D|O                                                                  ∥-III C--C--X                                                        |                                                                    CN                                                                            IV-B                                                            CH.sub.2 O O CH.sub.2                                                                            Maleic                                                     D |∥∥|D                                                      Anhydride                                                  C--C--O--R--O--C--C                                                                              →                                                   ||                                                                             (or Δ)                                               CN CN                                                                         V                                                                             O O                    O                                                      ∥∥   CH--C∠                                           CH.sub.2 = C--C--O--R--O--C--C=CH.sub.2 + 2                                                          D|O                                           ||   CH-- C∠                                          CN CN                  O                                                      VI                                                                            ______________________________________                                    

The monomeric esters (I) of 2-cyanoacrylic acid are well known and aredescribed in U.S. Pat. No. 2,794,788. Since the ester group issubsequently hydrolyzed, the identity of the R' group of Formula I ofthe Flow Chart is immaterial. Therefore, R' can be C₁ to C₁₆ alkyl,cyclohexyl or phenyl. For convenience, isobutyl 2-cyanoacrylate is thepreferred ester, R' being isobutyl. In the above scheme, it should alsobe noted that M denotes a monovalent, divalent or trivalent ion derivedfrom a metal hydride, hydroxide, carbonate, alkoxide, or anorganometallic agent.

Although the anthracene radical is preferred, in which case ##SPC6##

would be ##SPC7##

the 1,3-diene used to take part in the Diels-Alder adduct formation maybe selected from a large number of compounds with the adducted 1,3-dieneradical as represented by ##SPC8##

being any of the radicals ##SPC9##

where R₁ and R₂ are the same R₁ and R₂ may be H, an alkyl group of 1 to5 carbons, phenyl, Br or Cl. Where R₁ and R₂ are different, R₁ is H andR₂ may be any of the group consisting of an alkyl group of 1 to 5carbons, phenyl, Br and Cl. ##SPC10##

where R₃ is H or CH₃ and ##SPC11##

The organo linking group "R" appearing in the formulas of the above FlowChart may be any of the group consisting of

    --(CH.sub.2).sub.m --,

where m is an integer of from 1 to 20 inclusive; ##EQU5## where n is aninteger of from 0 to 18 inclusive, and R₄ and R₅ are independentlyhydrogen or a C₁ to C₅ alkyl group, R₄ and R₅ not simultaneously beinghydrogen;

    --(CH.sub.2).sub.r --Z--(CH.sub.2).sub.s --,

where Z is --O--, --S--, --CH=CH--, --C.tbd.C--, ##EQU6## and ##SPC12##

where r and s are independent integers of from 1 to 10 inclusive and rand s total from 2 to 20, R₆ and R₇ are independently hydrogen or astraight or branched chain C₁ to C₅ alkyl group; ##SPC13##

where x and y are integers of from 1 to 6 inclusive; ##SPC14##

where x and y are as hereinbefore defined;

    --CH.sub.2 -- (CF.sub.2).sub.z --CH 2--,

where z is an integer of from 1 to 10 inclusive; and ##EQU7## andwherein R' of Formula II is an alcohol moiety selected from C₁ to C₁₆alkyl, cyclohexyl or phenyl.

One of the advantages of the process, as set forth in the above FlowChart, is that it uses conventional reactions known to skilled chemists.These reactions however, have been utilized in a new and novel sequenceto produce highly useful bis cyanoacrylate products which previouslycould not be made.

Thus, the basic Diels-Alder reaction, going from Formula I to FormulaII, is a well known type of reaction known and used by skilled chemistsas is the saponification reaction followed by acidification used ingoing from the compound of Formula II to that of Formula III. However,compounds of the General Formula III were not known prior to mypreparation and discovery thereof and form a critical step in theoverall process described.

In like manner the metal salt-halide basic reaction is well known forlinking together two acyl groups (the route through IV-A) as is theother route, that through IV-B wherein the carboxylic acid group isfirst converted to the acid halide and then esterified through reactionwith a dihydroxy compound.

DETAILED DESCRIPTION OF THE INVENTION Preparaton of the Diels-AlderAdducts of 2-Cyanoacrylic Acid Esters of 2-Cyanoacrylic Acid

The difunctional monomers are prepared according to the method of thisinvention by the reaction of an ester of 2-cyanoacrylic acid (I) with a1,3-diene to form the intermediate Diels-Alder adduct (II). Thisreaction is suitably carried out in an inert solvent such as, forexample, benzene, toluene, or xylene or mixtures thereof. The reactiontemperature can be anywhere from 5°C to the reflux temperature of thesolution, depending on whether the reaction is exothermic orendothermic. The reaction is preferably carried out at the refluxtemperature in benzene as solvent or, where the reaction is exothermic,at the ambient reaction temperature or at room temperature and below.Suitable dienes include those which will undergo 1,4-cyclo-addition witha dienophile and which addition can be reversed after formation of themonomer adduct (V), such as, for example, by the application of heat orthe addition of a more reactive dienophile such as maleic anhydride.

In this regard, cyclic 1,3-dienes are much preferred over the acyclicdienes (e.g., butadiene, isoprene, 1,3-pentadiene), since they affordDiels-Alder adducts with endo-bridges and which are more prone towardssubsequent removal of the protective 1,3-diene moiety via aretrograde-diene scission. The bis-isoprene adduct intermediatecorresponding to adduct V, for example, is highly resistant towardsreverse Diels-Alder reaction, either thermally or by reaction withexcess maleic anhydride. Typical examples of suitable cyclic 1,3-dienesare anthracene, the 9-substituted and 9,10-disubstituted anthracenes(9-methylanthracene, 9-bromoanthracene, 9-phenylanthracene;9,10-dimethyl,-dibromo-, and -diphenylanthracenes), cyclopentadiene,methylcyclopentadiene, and norbornadiene. Preferred dienes from anavailability standpoint, ease of adduct formation and subsequentretrograde-diene scission to the difunctional monomer (VI) in goodyields and purity are anthracene, the 9-monosubstituted anthracene and9,10-disubstituted anthracenes, and cyclopentadiene.

The preferred dieneophile is isobutyl 2-cyanoacrylate, and the reactionof this latter cyanoacrylate with anthracene will yield theanthracene/isobutyl 2-cyanoacrylate adduct (II) in nearly quantitativeyield.

The 1,3-diene/alkyl 2-cyanoacrylate adduct (II) is then subjected tohydrolysis, preferably alkaline hydrolysis, to form the correspondingadduct of 2-cyanoacrylic acid (III). The hydrolysis is generally carriedout in an aqueous alcoholic solution comprising the adduct of the esterof 2-cyanoacrylic acid (II) and an alkali metal hydroxide, and thesolution is heated until the hydrolysis has been accomplished. Thereaction is complete after one to five hours at reflux, but it ispreferred to effect alkaline hydrolysis in as short a time as possible,preferably within one to two hours, to minimize or preclude concomitanthydrolysis of the cyano functional group. The hydrolyzed adduct is thenacidified with hydrochloric acid, for example, to a pH of 2 and thecrystalline Diels-Alder adduct (III) of 2-cyanoacrylic acid collected,washed with water, and dried.

Preparation of the Diels-Alder Adducts of 2-Cyanoacrylic Acid - MetalSalts and 2-Cyanoacryloyl Halides

The 2-cyanoacrylic acid adduct (III) is then converted to either the2-cyanoacryloyl halide adduct (IV-B) or the 2-cyanoacrylic acid - metalsalt adduct (IV-A).

The 2-cyanoacrylic acid - metal salt adduct (IV-A) is suitably preparedby neutralizing an alcohol or acetone solution of the 2-cyanoacrylicacid adduct (III) with an alcoholic solution of an alkali metalhydroxide. Generally, the alcoholic solution of the alkali metalhydroxide is added dropwise to the solution of the acid adduct (III)until the pH is about 9.0, which pH has been determined to be theequivalence point. Preferred alkali metal hydroxides are sodiumhydroxide and potassium hydroxide.

Alternate methods for preparation of the alkali metal salt adducts(IV-A) include the addition of stoichiometric quantities of alkali metalhydrides, preferably sodium hydride; alkali metal alkoxides, preferablysodium methoxide, sodium ethoxide, and potassium t-butoxide; alkalimetal carbonates such as sodium carbonate and potassium carbonate; andorgano lithium compounds such as butyl lithium and the like to thesolution or suspension of the 2-cyanoacrylic acid adduct (Formula III).

The preferred metal salts of the 2-cyanoacrylic acid adduct (III) arethose of the alkali metals in Group I of the Periodic Table, preferablysodium, potassium, and lithium. Adduct-metal salts (IV-A) of certain ofthe Group II elements, exemplified by magnesium, calcium, zinc, andbarium, and trivalent metals from Group III, such as aluminum, can alsobe prepared from the requisite metal oxides, metal hydroxides, and metalcarbonates.

The 2-cyanoacryloyl halides (IV-B) are prepared by reaction of the2-cyanoacrylic acid adduct (III) with the halide reactant, preferablythionyl chloride or thionyl bromide, under anhydrous conditions in asuitable dry solvent, e.g., benzene, and in an inert atmosphere. Whileonly a small excess of the thionyl halide reactant is required, a25-200% excess is preferably employed. Alternately, a still largerexcess of the thionyl halide can be utilized to function as both thesolvent and reactant. Reaction is enhanced by employing a very smallamount of either pyridine or N,N-dimethylformamide (DMF) asaccelerators. The reaction is effected in an inert atmosphere attemperatures ranging from 5°C to 80°C and for about one to four hours,or until reaction is completed, as indicated by cessation of theevolution of hydrogen chloride and sulfur dioxide. Acid halide adduct(IV-B) is isolated by distillation in vacuo to remove any solvent andunreacted thionyl halide and purified by recrystallization from an inertsolvent or, if sufficiently volatile, distillation under reducedpressure. A synthesis of the anthracene/2-cyanoacryloyl chloride adductis exemplified in Example VI.

The 2-cyanoacryloyl halide adduct (IV-B) can also be prepared byutilizing reacants such as phosphorus trichloride and phosphoruspentachloride, whose use is well known to those skilled in the art.

After formation of either the adduct of 2-cyanoacrylic acid alkali metalsalt (IV-A), or of the adduct of 2-cyanoacryloyl halide (IV-B), theserespective intermediates are employed by respective reaction with adihalide or diol to form the bis-Diels-Alder adduct of the bis(2-cyanoacrylate) monomer (V).

Preparation of the Bis-Diels Alder Adducts (V) of Bis (2-Cyanoacrylate)Monomers

In general, about two moles of the Diels-Alder adduct (IV-A or IV-B) areemployed for each mole of dihalide or diol reactant. Suitable dihalideor diol reactants include organic compounds having two reactive halogenor hydroxy substituents thereon, the dihalide of which will undergo adisplacement reaction with the carboxylate salt and the diols of whichundergoes an acrylation reaction with the 2-cyanoacryloyl halide to formthe bis-Diels-Alder adducts (V) of the bis (2-cyanoacrylate) monomers.Examples of such compounds, wherein X is either independently selectedfrom the halogens chlorine, bromine, iodine, or from hydroxy, include:

A. X--(CH₂)_(m) --X, where m is an integer of from 1 to 20 inclusive,such as methylene iodide, 1,3-dibromopropane, 1,9-dibromononane,1,12-dibromododecane, 1,3-propanediol, 1,9-nonanediol, and1,12-dodecanediol. ##EQU8## where n is an integer of from 0 to 18 and R₄and R₅ are independently selected from the group consisting of hydrogenand C₁ to C₅ alkyl, but R₄ and R₅ not simultaneously being hydrogen;such as 1,3-dibromobutane, 2,5-dibromohexane, 1,3-butanediol, and2,5-hexanediol.

C. X--(CH₂)_(r) --Z--(CH₂)_(s) --X, where Z is --O--, --S--, --CH=CH--,--C.tbd.C--, ##EQU9## and ##SPC15##

where r and s are independent integers of from 1 to 10 inclusive and rand s total from 2 to 20, R₆ and R₇ being as heretofore defined. Thesubstitution on the aromatic ring is meta, para, or ortho; meta or parabeing preferred. The hydrogen atoms of the vinyl substituent are eithercis or trans. Examples include: 2-chloroethyl ether, diethylene glycol,4-chlorobutyl ether, 4-hydroxybutyl ether, 2-chloroethyl sulfide,2-hydroxyethyl sulfide, 3-chloropropyl sulfide, 3-hydroxypropyl sulfide,trans-1,4-dibromo-2-butene, trans-2-butene-1,4-diol,trans-1,8-dichloro-4-octene, trans-4-octene-1,8-diol,trans-1,12-dichloro-6-dodecene, trans-6-dodecene-1,12-diol,1,4-dichloro-2-butyne, 2-butyne-1,4-diol, 1,8-dichloro-4-octyne,4-octyne-1,8-diol, 1,12-dichloro-6-dodecyne, 6-dodecyne-1,12-diol,1,3-dibromo-2,2-dimethylpropane,-dihydroxy-1,3-dihydoxy-2,2-dimethylpropane, 4,4'-bis (chloromethyl)diphenyl ether, 4,4'-bis (hydroxymethyl) diphenyl ether and neopentylglycol.

D. Alkylene glycols of the formula HO[R"O--_(t) H, where when t is ≧ 1,R" is propylene, and when t is > 2, R" is also 1,4-tetramethylene andethylene. The polyalkylene glycols are suitable in the higher molecularweight ranges generally to about a molecular weight of about 2000.Examples include propylene glycol, dipropylene glycol, polypropyleneglycol, triethylene glycol, tetraethylene glycol, polyethylene glycol,and poly (1,4-tetramethylene glycol).

E. ##SPC16##

where the substitution on the aromatic ring is meta, para, or ortho, andx and y are integers of from 1 to 6 inclusive such as1,4-bis(chloromethyl) benzene, 1,4-bis(hydroxymethyl) benzene,1,4-bis(4-bromobutyl) benzene, 1,4-bis(4-hydroxybutyl) benzene,1-chloromethyl-4-(4-chlorobutyl) benzene and1-hydroxymethyl-4-(4-hydroxybutyl) benzene.

F. ##SPC17##

where x and y are as hereinbefore defined and the substitution on thecyclohexane ring is 1,2; 1,3; or 1,4 such as 1,4-bis(chloromethyl)cyclohexane, 1,4-bis(hydroxymethyl)cyclohexane,1,4-bis(4-bromobutyl)cyclohexane, 1,4-bis(4-hydroxybutyl) cyclohexane,1-chloromethyl-4-(4-chlorobutyl)cyclohexane, and1-hydroxymethyl-4-(4-hydroxybutyl) cyclohexane.

G. X--CH₂ --(CF₂)_(z) --CH₂ --X, where z is an integer of from 1 to 10inclusive such as 1,5-dibromo-2,2,3,3,4,4-hexafluoropentane,1,5-dihydroxy-2,2,3,3,4,4-hexafluoropentane,1,10-dibromo-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorodecane, and1,10-dihydroxy-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorodecane.

H. X--CH₂ --Si(CH₃)₂ --O--Si(CH₃)₂ --CH₂ --X such as1,3-bis(chloromethyl)tetramethyldisiloxane or1,3-bis(hydroxymethyl)tetramethyldisiloxane.

The reactants, metal salt adduct (IV-A) and dihalide, are admixed in dryN,N-dimethyl formamide (approximately 2 ml. per gram of combinedreactants) and are heated with stirring at 50° to 150°C for from 10minutes to 24 hours. The resulting solution, containing suspended alkalimetal halide solids, is then added in small increments with stirring to10 volumes of water. The precipitate of bis-anthracene adduct (V) iscollected by suction-filtration, washed thoroughly with water, andair-dried to constant weight. The adduct can suitably be furtherpurified by recrystallization from an appropriate solvent and/orchromatography on alumina, activity grade I, acid or neutral. Inchromatographic purification, bis-anthracene adducts are eluted rapidlyfrom the column with the less polar solvents, e.g., benzene,benzene-hexane, or benzene-chloroform blends. Polar impurities anddegradation products are usually selectively adsorbed and retained onthe chromatographic column.

When the bis-anthracene adduct is obtained as a gummy or oily product onaddition to water in the above procedure, it is extracted into eitherbenzene or chloroform. The extract is backwashed thoroughly with water,dried over anhydrous magnesium sulfate, and solvent stripped. Residualadduct, generally a low melting solid or gum, is best purified furtherby column chromatography as described. Purification of bis-anthraceneadducts is much preferred in order to obtain good yields of high puritybis (2-cyanoacrylate) monomers in the next and last step in thesynthetic sequence.

In the alternate method for bis-anthracene adduct (V) formation from the2-cyanoacryloyl halide adduct (IV-B), the latter can be prepared in situand then reacted with the diol or it can be isolated as a pureintermediate and used as such.

For example, a reaction mixture consisting of equimolar quantities ofthe anthracene/2-cyanoacrylic acid adduct (III) and thionyl chloride inbenzene (about 3 ml. per gram of total reactants) containing a smallamount of pyridine or DMF as accelerator is stirred at from 5°C to 80°Cat from one to four hours or until reaction is completed (cessation ofevolution of hydrogen chloride and sulfur dioxide). To the solution ofin situ produced acid chloride adduct is added dropwise, with stirring,a solution of the stoichiometric quantity of the diol and excesstriethylamine dissolved in approximately an equal volume of DMF. Thereaction is exothermic and can be effected at the ambient temperature orpreferably, at reduced temperatures such as 5°C to 25°C. Reaction isessentially instantaneous and can be effected, depending on rate ofaddition and temperature control, within 15 minutes to three hours. Thereaction mixture is then diluted with additional benzene and extractedrepeatedly with water. After drying the benzene extract and solventstripping, the crude bis-anthracene adduct (V) is purified by eitherrecrystallization from a suitable solvent or chromatography on alumina,activity grade I, acid or neutral, as hereinbefore described.

The pure anthracene/2-cyanoacryloyl chloride adduct, for example, can beprepared by reaction of the 2-cyanoacrylic acid adduct (III) withstoichiometric quantities or a 25-200% excess of thionyl chloride inrefluxing benzene (about 2 to 10 ml. per gram total reactants) or otherinert solvent until reaction is completed, as indicated by completesolution of the adduct (III) and cessation of evolution of hydrogenchloride and sulfur dioxide. The solvent and excess thionyl chloride areremoved by distillation in vacuo and the crude acid chloride adductpurified by recrystallization from an inert solvent, such as benzene orbenzene-hexane blends.

The anthracene/2-cyanoacryloyl chloride adduct (IV-B) thus prepared isdissolved in dry DMF (about 1-5 ml. per gram acid halide). Withstirring, a solution of the stoichiometric quantity of the diol and anexcess of triethylamine in one to five volumes of dry DMF is addeddropwise over 15 minutes to three hours and at temperatures ranging from5°C to the ambient temperatures generated from the exothermic reaction.Bis-anthracene adduct (V) is isolated by quenching the reaction mixturein ten volumes of water. The precipitated bis-anthracene adduct (V) isfiltered, washed well with water, dried, and purified byrecrystallization from a suitable solvent or by chromatography onalumina. If the crude adduct obtained on quenching in water is a gum oroily product, it is isolated and purified by either of severalprocedures hereinbefore described.

Displacement of the Diene Protecting Group from Adduct V to YieldDifunctional Monomers

The displacement of the protecting group can be performed by heating,but in many instances the temperature required to achieve displacementof the protecting group will risk polymerization, or at leastdegradation, of the difunctional monomer. Therefore, the preferreddisplacement is effected under lower temperature conditions in thepresence of a more reactive dienophile exemplified by maleic anhydride.The bis-anthracene adduct is reacted with at least an equivalent amount,preferably with an excess, and most preferably a 50-200% excess ofmaleic anhydride. The reaction mixture is dissolved in suitable inertsolvent such as xylene or benzene, xylene being preferred. Where xyleneis used the mixture is heated with stirring at about 140°C, the refluxtemperature of the solvent. This heating is continued for 7-24 hours oruntil reaction is completed and the reaction mixture cooled to roomtemperature. The anthracene/maleic anhydride (A/MA) byproduct whichcrystallizes out in high yields is collected suitably bysuction-filtration, for example, and washed thoroughly with dry SO₂-treated benzene. The filtrate is solvent stripped at about 50°C underreduced pressure to a residue, from which the xylene is removed byrepeated additions of dry benzene and solvent stripping to a residue(monomer, excess maleic anhydride, and residual A/MA adduct).

The flask containing the crude monomer is connected to a receiver flaskfitted with a condenser and a vacuum take-off adapter on top of thecondenser. The receiver flask is cooled in a solid carbon dioxide bath,and the flask containing the monomer and excess maleic anhydride heatedwith stirring at 50° to 100°C, preferably 60°-80°C (oil bathtemperature), and at 0.1-0.2mm pressure. Excess maleic anhydride readilysublimes off and is collected largely in the cooled receiver flask. Anyresidual maleic anhydride on the inside, upper walls of the flask can bedriven off with gentle heating with a jet of heated air. The flaskcontents, after cooling to room temperature, are taken up in dry, SO₂-inhibited benzene and cooled to room temperature. Additional smallamounts of A/MA adduct and polymeric by products are usually filteredoff at this stage. Concentration of the filtrate and crystallizationfrom either benzene or benzene-hexane in the cold affords thecrystalline bis (2-cyanoacrylate) monomers. Where the monomer is aliquid, as much of the residual A/MA adduct is fractionally crystallizedout as possible and the solution solvent stripped to give the liquidmonomer.

The following detailed examples will serve to provide specificillustration of the methods of preparing the difunctional monomers.

EXAMPLE I Preparation of11-Cyano-11-carboisobutoxy-9,10-dihydro-9,10-endoethanoanthracene (II)

A solution of 178.2 g (1.00 mole) anthracene (>98% purity) and 153.2g(1.00 mole) isobutyl 2-cyanoacrylate (IBC) in 1000 ml. dry, SO₂-inhibited benzene is refluxed for 17 hours. The yellow solution isconcentrated to a volume of about 600 ml. and cooled in a refrigerator.The crystalline adduct is then suction-filtered, washed with benzene andhexane, and air-dried. The yield is 224.5 g, mp. 77°-79°C. The filtrateis solvent stripped and the residue recrystallized from 350 ml. 95%ethanol to give two additional crops of product: 100.1 g, mp 92°-96°C,and 15.2 g, mp 94°-98°C. The three crops of crystals are combined andrecrystallized from 95% ethanol to give several crops of purifiedproduct: 234.5 g, mp 99°-100°C; 29.0 g, mp 98.5°-100°C; 9.5 g, mp100.5°-101.0°C. The total yield is 273 g or 82.5% of theory.

An analytical sample, recrystallized from 95% ethanol and dried over P₂O₅ at 60°C/0.4 mm, showed a mp of 100°-101°C.

Anal: Calcd. for C₂₂ H₂₁ NO₂ : C, 79.73%; H, 6.39%; N, 4.23%. Found: C,79.58%; H, 6.23%; N, 4.00%.

EXAMPLE II Preparation of11-Cyano-9,10-dihydro-9,10-endoethanoanthracene-11-carboxylic acid (III)

Into a 3-liter round bottom flask fitted with a mechanical stirrer,condenser, and heating mantle is charged 248 g (0.750 mole)anthracene/IBC adduct, 900 ml. 95% ethanol, and a solution of 73.3 g(1.13 moles) of potassium hydroxide (86.4%) dissolved in 375 ml. water.The deep red colored (sometimes a transient violet color) solution isstirred at reflux for 1.5 hours. The pale orange colored solution isquenched into 4000 ml. water. After standing at room temperatureovernight, the suspension (free anthracene) is filtered and the filtercake washed thoroughly with water. The clear yellow filtrate isacidified to pH 2 by the dropwise addition with stirring of 6 Nhydrochloric acid. The crystalline white solids are collected, washedwith water, and air-dried to constant weight. The yield ofanthracene/2-cyanoacrylic acid adduct, mp 201°-202° dec., is 189.0 g(91.8% theory).

Neutralization Equivalent: Calcd: 275.31

Found: 277.8

An analytical sample, recrystallized from acetone/hexane, showed mp.208°-209°C. dec.

Anal: Calcd for C₁₈ H₁₃ NO₂ : C, 78.53%; H, 4.76%; N, 5.09%; Found: C,78.46%; H, 4.69%; N, 5.35%

EXAMPLE III Alternate Preparation of11-Cyano-9,10-dihydro-9,10-endoethanoanthracene-11-carboxylic acid (III)

A mixture consisting of 356.6g (2.00 moles) anthracene (98+%) and 306.4g(2.00 moles) isobutyl 2-cyanoacrylate in 2000 ml. benzene is refluxedfor 4.5 hours and cooled to room temperature. No unreacted anthracenecrystallized from the solution. The latter is solvent stripped on asteam bath at water aspirator pressures to a heavy slurry of crystallinesolids. Ethanol (500 ml) is added to the solids residue and thesuspension stripped to a pasty solids residue again. This process isrepeated with another 2× 500 ml. 95% ethanol in order to strip off thebulk of the residual benzene. The residue is diluted with 2000 ml.ethanol. A solution of 195 g (3.00 moles) of potassium hydroxide (86%w)in 1000 ml. water is then added. The reaction mixture is stirred at amoderate reflux for two hours, quenched in 7000 ml. water, and theprecipitated anthracene (42.5g, mp 212°-216°C) filtered off afterstanding at room temperature overnight. The filtrate is acidified to pH2.0 with 6N hydrochloric acid, and the precipitated adductsuction-filtered, washed thoroughly with water, and air-dried toconstant weight. The yield of anthracene/2-cyanoacrylic acid adduct is482.3g (88% theory), mp 200°-204° dec.

Adduct yields in five other runs ranged from 89 to 93%. Recovery ofanthracene is about 5-12% w of that charged.

EXAMPLE IV Preparation of Potassium11-Cyano-9,10-dihydro-9,10-endoethanoanthracene-11-carboxylate (IV-A)

Into a 5 liter three-neck round bottom flask fitted with a mechanicalstirrer, dropping funnel, and single probe pH electrode is charged asolution of 530 g (1.93 moles) of anthracene/2-cyanoacrylic acid adductin 2000 ml. absolute methanol. With stirring and dropwise addition of asolution of 20% w/v potassium hydroxide in 95% ethanol, the solution pHis adjusted from 2.0 to the equivalence point, generally 9.0-9.1 pH. Thesuspension of solids is solvent stripped in vacuo to a pasty solidsresidue. Residual alcoholic solvent is removed by dilution with 500 mlacetone and stripping to moist solids. The solids are suspended in 2500ml. acetone, stirred well at room temperature for one hour,suction-filtered, and the white solids washed thoroughly with acetone.The yield of adduct-potassium salt is 603 g (100% theory).

EXAMPLE V Anthracene/2-Cyanoacrylic Acid Adduct - Sodium Salt (IV-A)

A solution of 19.1 g (0.0695 mole) anthracene/2-cyanoacrylic acid adductin 100 ml. 95% ethanol is adjusted to the equivalence point by thedropwise addition of 50%w aqueous sodium hydroxide solution. Heavycrystallization of solids takes place on cooling to room temperature.The suspension is concentrated on a rotating evaporator to white solidswhich are dried in a desiccator over Drierite for two days and then in avacuum oven at 60°C for three hours. The yield of adduct-sodium salt is22.2g. The infrared spectrum is consistent with the proposed structure.

EXAMPLE VI Anthracene/2-Cyanoacryloyl Chloride Adduct (IV-B)

A mixture consisting of 5.5 g (0.020 mole) anthracene/2-cyanoacrylicacid adduct, 2.9 ml. (0.040 mole) thionyl chloride, and 20 ml. drybenzene containing one drop of pyridine as accelerator is heated atreflux under nitrogen for two hours. On cooling to room temperature,heavy crystallization of the acid chloride adduct takes place. Thebenzene and excess thionyl chloride are removed on concentrating thesuspension to dryness under reduced pressure with a rotating evaporator.The crude residual product is recrystallized from 1:1 dry benzene-hexaneto give 4.7g of adduct, mp 77°-86°C, faint yellow needles. Concentrationof the mother liquors gives another 0.7g adduct, mp. 79°-81°C. Thecombined yield of 5.4g is 92% of the theoretical amount.

Infrared and NMR spectral data are consistent with the structure of theadduct. Further proof of structure is obtained on conversion of the acidchloride adduct with ethanol and ethylene glycol, respectively, to theanthracene/ethyl 2-cyanoacrylate (mp 123°-125°C) andbis-anthracene/ethylene glycol bis (2-cyanoacrylate) (mp 206°-210°C)adducts.

EXAMPLE VII Bis-Anthracene Adduct of Ethylene Glycol Bis(2-Cyanoacrylate) (V) - via Potassium Salt Adduct (IVA)

A suspension of 62.7 g (0.200 mole) anthracene/2-cyanoacrylic acidadduct-potassium salt and 18.8 g (0.100 mole) 1,2-dibromoethane in 150ml. of dry DMF is heated with stirring to 100°C. The adduct-potassiumsalt is solubilized within about 10 minutes followed by the depositionof finely divided potassium bromide. After one hour at 100°C, thereaction mixture is added dropwise with stirring to 1500 ml. of water.The suspended product is stirred for one hour, collected viasuction-filtration, washed thoroughly with water and lastly with a largevolume of 95% ethanol (to remove entrained water and ethanol solubleimpurities). The yield of bis-anthracene adduct is 48.7 g, mp203°-206°C. A second crop of 4.4 g, mp 203.0°-206.5°C, deposited slowlyfrom the ethanolic filtrate. The total yield is 53.1 g (92% theory).

In five runs on a 0.1 to 0.8 molar scale, the yields of adduct ranged75-94% of theory.

EXAMPLE VIII Bis-Anthracene Adduct of Ethylene Glycol Bis(2-Cyanoacrylate) (V) via the Sodium Carboxylate Salt Adduct (IVA)

To a stirred solution of 13.8g (0.05 mole) anthracene/2-cyanoacrylicacid adduct in 50 ml. dry DMF is added, in portions, 2.40g (0.05 mole)sodium hydride (50% in oil). Effervescence (hydrogen evolution) and amild exotherm takes place during the in situ formation of the sodiumsalt. The suspension of solids is cooled to room temperature and 4.7g(0.05 mole) 1,2-dibromoethane added. The reaction mixture is stirred atroom temperature for 17 hours with no apparent reaction (an aliquotdeposited heavy white precipitate of acid adduct on acidification). Thesuspension, on heating to 100°C, becomes homogeneous. After three hoursreaction at 100°C, the mixture is quenched in 400 ml. water to give 13.3g of crude bis-adduct, mp 93°-143°C. Chromatography on 136g alumina,acid, activity grade I, and elution with benzene and benzene-chloroformgives several fractions of purified adduct. Recrystallization fromeither benzene or acetone/hexane gives several crops (4.0g total, 28%theory) of the bis-anthracene adduct of ethylene glycol bis(2-cyanoacrylate) showing mp. 204°-209°, 202°-205°, 205.5°-209.0°,209°-211.5°, and 202°-205°C.

EXAMPLE IX Bis-Anthracene Adduct of Ethylene Glycol Bis(2-Cyanoacrylate) (V) via Anthracene/2-Cyanoacryloyl Chloride AdductFormed In Situ (IVB)

Into a 250 ml. round bottom flask fitted with a stirrer, thermometer,and nitrogen inlet adapter is charged, under nitrogen, 10.0g (0.0364mole) anthracene/2-cynoacrylic acid adduct, 50 ml. dry benzene, 1.0 ml.DMF (as accelerator), and 4.4 ml (0.037 mole) thionyl chloride. Thesuspension is stirred at room temperature for 15 minutes and heated to50°C (complete solution took place). After three hours at 60°C, theorange solution is cooled to room temperature. With stirring, a solutionof 1.13 g (0.0182 mole) ethylene glycol and 3.68 g (0.0364 mole)triethylamine in 5 ml. DMF is added dropwise over 15 minutes. A moderateexotherm ensues, depositing fine solids (Et₃ N.HCl). Since the resultantsuspension is still acidic, another 1.0 ml. of triethylamine was addedand the mixture stirred at room temperature for 1.25 hours. The reactionmixture is diluted with 50 ml. benzene and the solution washed fourtimes with water. The benzene extract is dried over anhydrous magnesiumsulfate, filtered, and solvent stripped to gummy yellow-orange solids(10.0g). Crystallization from acetone gives 0.7g of crude product, mp188°-210°C. Solvent stripping of the filtrate and slurrying of the gummyresidue in 100 ml. of hot ethanol gives another 5.8g, mp. 188°-197°C, ofyellow solids. The two crops are combined (6.5g, 62% yield) and slurriedin hot ethanol (300 ml) to give 4.1 g (39% theory) or purified product,mp 192°-201°C. Recrystallization from chloroform/ethanol gives 2.9gshowing mp 201°-203°C. Further purification via chromatography on 25galumina, acid, activity grade I, and elution with chloroform gives 1.3gof pure bis-anthracene adduct, white crystals, mp 208.5°-209.5°C.

EXAMPLE X Bis-Anthracene Adduct of Ethylene Glycol Bis (2-Cyanoacrylate)(V) via Pure Anthracene/2-Cyanoacryloyl Chloride Adduct (IVB)

Into a reaction flask fitted with an addition funnel, thermometer,drying tube, and magnetic bar stirrer is charged 5.9g (0.020 mole)anthracene/2-cyanoacryloyl chloride adduct and 5.0 ml. dry DMF. Withstirring, a solution consisting of 0.62g (0.010 mole) ethylene glycoland 3.0 g (0.030 mole) triethylamine in 5 ml. dry DMF is added dropwiseover about 30 minutes. The reaction is exothermic, and the temperatureis maintained at about 23°C with external cooling during the additionstep. The flask contents are poured into 150 ml. water, and the gummyproduct is extracted into 2×50 ml. benzene. After backwashing thecombined extracts with water, the extract is solvent stripped to give4.9g of a gum. On stirring in 100 ml. boiling 95% ethanol, the gum isconverted to white solids of the bis-anthracene adduct, 3.1g. mp206°-210°C. A mixed mp with adduct prepared via the potassiumcarboxylate adduct and 1,2-dibromoethane showed mp 205°-210° C, or nodepression.

EXAMPLE XI Ethylene Glycol Bis (2-Cyanoacrylate); (EGBCA)

A suspension of 62.7 g (0.200 mole) anthracene/2-cyanoacrylic acidadduct-potassium salt and 18.8 g (0.100 mole) 1,2-dibromoethane in 150ml. of dry DMF is heated with stirring to 100°C. The adduct-potassiumsalt is solubilized within about 10 minutes followed by the depositionof finely divided potassium bromide. After one hour at 100°C, thereaction mixture is added dropwise with stirring to 1500 ml. of water.The suspended product is stirred for one hour, collected vissuction-filtration, washed throughly with water and lastly with a largevolume of 95% ethanol (to remove entrained water and ethanol solubleimpurities). The yield of bis-anthracene adduct is 48.7 g, mp203°-206°C. A second crop of 4.4 g, mp 203.0-206.5°C, deposited slowlyfrom the ethanolic filtrate. The total yield is 53.1 g (92% theory).

In five runs on a 0.1 to 0.8 molar scale, the yields of adduct ranged75-95% of theory.

A mixture of 57.5g (0.100 mole) bis-anthracene/EGBCA adduct, 58.8 g(0.600 mole) maleic anhydride, 200 ml. dry xylene (SO₂ -inhibited), 0.2g hydroquinone, and 1.0 g phosphorous pendoxide is heated at 140°-145°Cfor 7 hours. The resultant suspension is cooled to room temperature andthe anthracene/maleic anhydride adduct (A/MA) is collected, washed wellwith dry benzene, and oven-dried, yield=50.7 g (92% theory), mp260-265°C. The filtrate is solvent stripped to a liquid residue anddiluted with 3 × 100 ml. dry benzene and solvent stripped each time to aresidue. The semicrystalline residue is taken-up in 100 ml benzene, letstand at room temperature one hour, and filtered to give an additional6.6 g, mp 248°-256°C, of A/MA adduct. The filtrate is solvent stripped,and the excess maleic anhydride is sublimed off at 70°C (0.2mm).Dilution of the crystalline residue with 75 ml. dry benzene gave another1.7 g, mp 246°-258°C, of A/MA. The total recovery of A/MA adduct is 59.0g (107% theory).

The filtrate is solvent stripped and the residue slurried in 50 mlbenzene, cooled in an ice bath one hour, suction-filtered, and the whitecrystals washed with benzene to give 8.7 g, mp 103°-105°C, of ethyleneglycol bis (2-cyanoacrylate) monomer (EGBCA).

The following additional crops of EGBCA were isolated after solventstripping of the mother liquors, sublimation of small additional amountsof maleic anhydride, and crystallization from benzene: 3.1 g, mp99°-103°C; 3.0 g, mp 100°-104°C; 0.3 g, mp 98°-103°C. The total yield ofEGBCA is 15.1g (69% theory).

An analytical sample, recrystallized twice from benzene, showed mp104°-105°C.

Anal: Calcd for C₁₀ H₈ N₂ O₄ : C, 54.55%; H, 3.66%; N, 12.72%. Found: C,54.75%; H, 3.69%; N, 12.61%.

The IR and NMR spectra were consistent with the proposed structure. Themonomer was soluble in practically all common organic solvents, e.g.,acetone, chloroform, dioxane, ethyl acetate and aromatic hydrocarbons(warm), but not in the aliphatic hydrocarbons.

EXAMPLE XII 1,3-Propanediol Bis (2-Cyanoacrylate)

In a manner analogous to Example I, a mixture consisting of 62.7g (0.200mole) anthracene/2-cyanoacrylic acid adduct-potassium salt, 20.2 g(0.100 mole) 1,3-dibromopropane, and 165 ml dry dimethylformamide (DMF),is heated at 100°C for one hour and added dropwise with stirring to 1800ml. water. The white solids are collected, washed with water, andair-dried to give 51.2 g, mp 95°-106°C. of adduct. A second crop, 2.9 g,mp. 91°-101°C, can be recovered from the filtrate. The total yield is54.1g (91.5% theory). The NMR and IR spectra are consistent with thebis-adduct structure.

Reaction of 47.2 g (0.080 mole) bis-anthracene/1,3 propanediol bis(2-cyanoacrylate) adduct, 47.2 g (0.480 mole) maleic anhydride, 190 ml.dry xylene (SO₂), 0.1 g hydroquinone, and 0.5 g phosphorous pentoxide at140°-145°C for four hours gives 42.9 g (97% theory) of A/MA adduct, somepolymeric gel, and three crops (7.1 g, 38% theory) of product monomershowing mp 74°-78°, 75°-77° and 64°-77°C. Recrystallization from drybenzene gave additional polymer (orange gum) and 6.1 g (33% theory) ofpure product monomer, mp 79°-81°C.

EXAMPLE XIII 1,4-Butanediol Bis (2-Cyanoacrylate); (1,4-BDBCA)

Similarly, 15.7 g (0.05 mole) anthracene/2-cyanoacrylic acidadduct-potassium salt and 5.4g (0.025 mole) 1,4-dibromobutane in 40 ml.dry DMF are heated one hour at 100°-105°C and quenched in 400 ml. waterto yield 13.1 g, mp. 162°-172°, and 1.2 g, mp. 166°-169°C, of crudeadduct. Recrystallization from chloroform/ethanol gives 12.7 g (84%theory) of purified bis-adduct, mp 168°-175°C.

TLC (1:1 CHCl₃ /C₆ H₆): Rf 0.34 + trace amounts of impurities. All TLCprocedures described herein were conducted on Eastman 6060 Silica Gelchromatogram sheet.

Recrystallization of the 12.7 g adduct from 150 ml. benzene gives 10.9 gwhite crystals, mp. 198°-203°C, the higher melting polymorphic form.Concentration of the mother liquors gives two of the polymorphic formsshowing mp 175°-176°C and mp 198°-206°C.

It should be noted that mixtures of two or more polymorphic forms ofbis-adduct are generally isolated. This gives rise to a numberproduct-crops showing wide melting point ranges (e.g. 164°-201°C).Heating in various solvents can often suffice to convert one form intoanother.

A mixture of 30.2 g (0.05 mole) bis-anthracene/1,4-butanediol bis(2-cyanoacrylate) adduct, 29.4 g (0.300 mole) maleic anhydride, 100 ml.dry xylene (SO₂), 0.1 g hydroquinone, and 0.5 g of pbosphorous pentoxideis heated at 137°-143°C for 7 hours. Work-up according to the generalscheme gives 27.2 g (99% theory) of A/MA adduct and a total of fivecrops (7.4 g, 60% theory) of monomer, mp. 76-79, 76-78, 75-82, 77-79.Recrystallization from toluene and toluene-hexane gives 4.5 g, mp77.5-79.0 °C, and 0.7 g, mp 78.5°-80.0°C, of pure 1,4-BDBCA monomer (42%theory).

EXAMPLE XIV trans-2-Butene-1,4-Diol Bis (2-Cyanoacrylate); (t-1,4-BDBCA)

Reaction as above of 62.7 g (0.200 mole) anthracene/2-cyanoacrylic acidadduct-potassium salt and 21.4 g (0.100 mole) trans-1,4-dibromo-2-butenein 160 ml. dry DMF at 100°C for one hour followed by addition to 1600ml. water gives 60.1 g, mp. 93°-100°C. and 1.9 g, mp 93°-95°C, ofmethanol-washed adduct. Recrystallization of the combined solids frombenzene give two crops of adduct: 25.3 g, mp 104°-107°C, and 11.7g, mp145°-148°C. A third crop, 11.4 g, mp 148°-150°C, is obtained on additionof hexane to the mother liquors. Total yield, 48.4 g (80% theory).

The first crop (25.3 g), on suspension in 250 ml boiling ethanol andfiltration, yields 19.4 g, mp. 178°-179°C., of the higher meltingpolymorphic form. Combination of the second and third crops (23.1g) andslurrying in hot ethanol gives another 20.8 g, mp. 149°-152°C, of thelower melting polymorph. Further work-up of various mother liquors gives2.3 g white crystals (from benzene) showing mp 101.5°-108°C. All threepolymorphic forms of the bis-adduct showed Rf 0.5 on TLC in 1:1 CHCl₃/C₆ H₆.

A mixture consisting of 36.2 g (0.06 mole)bis-anthracene/trans-2-butene-1,4-diol bis (2-cyanoacrylate) adduct,35.3 g (0.36 mole) maleic anhydride, 120 ml. dry xylene (SO₂), 0.12 ghydroquinone, and 0.6 phosphorous pentoxide is stirred at gentle refluxfor 7 hours and cooled to room temperature. The crystalline A/MA adductis collected, washed with dry benzene, and dried in vacuo; yield = 30.3g (92% theory), mp 256°-257°C. The filtrate is solvent stripped to aliquid residue which is redissolved in several portions of dry benzeneand solvent stripped to a residue each time. The residue, oncrystallization from 50 ml. benzene in an ice bath, gives 6.4 g of crudemonomer, mp 108°-120°C. The crude monomer is slurried in 50 ml. boilingbenzene and filtered hot from the two crops of insoluble A/MA adduct(2.6 g, mp 257°-260°C and 0.4g, mp. 255°-260° C). The benzene solubles,on concentration and crystallization from benzene/hexane, afford 2.0 g,mp 106°-108°, and 0.6 g, mp 105°-108°C of additional monomer.

The mother liquor from the 6.4 g monomer fraction is solvent strippedand additional maleic anhydride sublimed off at 80°C (0.1 mm).Crystallization of the residue from 25 ml. benzene gives 6.3 g, mp.104-105°C (162° clear melt), and 2.9 g, mp. 103°-104°C, of monomer. Thetotal yield of t-1,4-BDBCA monomer is 11.8 g (80% theory).

Recrystallization from benzene of combined monomer (19.1g) from two runsgives some polymeric solids and 12.8 g of pure t-1,4-BDBCA, mp105°-107°C, white needles. Concentration of the mother liquors gives twoadditional crops; 0.9 g, mp 100°-105°C, and 1.3 g, mp 93°-105°C.

The total yield of A/MA adduct recovered is 33.3g (100% theory).

EXAMPLE XV 2,5-Hexanediol Bis (2-Cyanoacrylate); (2,5-HDBCA)

A mixture of 62.7g (0.200 mole) of anthracene/2-cyanoacrylic acidadduct-K salt, 24.4 g (0.100 mole) 2,5-dibromohexane, and 150 ml of dryDMF are heated at 100°C for one hour and added dropwise to 1500 mlwater. The white solids are collected, washed with water, and air-dried.The yield of bis-adduct, mp 84°-86°C, is 60.0 g (94.8% theory).

Bis-adduct from another run showed mp. 87°-92°C; TLC (1:1 CHCl₃ /C₆ H₆):Rf 0.6.

A mixture consisting of 56.0 g (0.0885 mole) bis-anthracene/2,5-HDBCAadduct, 52.0 g (0.531 mole) maleic anhydride, 0.1 g hydroquinone, and1.0 g phosphorous pentoxide in 220 ml. dry, SO₂ inhibited xylene isheated at 138°-142°C for 8 hours, cooled to room temperature, andfiltered to give 31.7 g, mp 264°-268°C, of the A/MA adduct. Aftersolvent stripping to remove residual xylene, the excess maleic anhydrideis sublimed off at 65°-80°C/0.2 min. The orange gummy residue isrecrystallized from benzene in the cold to give another 5.5 g, mp261°-267°C, of A/MA adduct. Concentraton of the filtrate andcrystallization from benzene/hexane gives 0.8 g of white solids showingmp 73°-190°C. Further concentration and cooling give additional whitesolids. The latter are collected, washed successively with benzene, 1:1benzene/hexane, and hexane to give 1.6 g of product monomer, mp 80.0° -80.5°C.

EXAMPLE XVI 1,3-Bis(Hydroxymethyl) Benzene Bis (2-Cyanoacrylate)

A mixture consisting of 15.6 g (0.050 mole) anthracene 2-cyanoacrylicacid adduct-K salt and 4.3 g (0.025 mole) 1,3-bis (chloromethyl) benzenein 40 ml. dry DMF is heated at 100°C for one hour and added dropwise,with stirring, to 500 ml. water. The fine solids are collected bygravity filtration, washed with water and methanol, and air-dried togive 10.5 g pale yellow solids, mp 105°-110°C. Two additional crops, 0.2g, mp 113°-118°C, and 2.3 g, mp 98°-104°C, are obtained by concentrationof the methanolic washes. The total yield is 13.0 g (82% theory). TLC(1:1 CHCl₃ /C₆ H₆): Rf 0.6 (bis-adduct) + Rf 0.9 (anthracene) + tracesof polar impurities (for all three crops).

In another run on a 0.05 mole scale, the yield of crude bis-adduct, mp.86°-88°C, was 30.9 g (98% theory), white solids.

A mixture consisting of 30.0 g (0.0474 mole) bis-anthracene adduct/1,3-bis (hydroxymethyl) benzene bis (2-cyanoacrylate), 27.8 g (0.284mole) maleic anhydride, 0.1 g hydroquinone, and 0.5 g phosphorouspentoxide in 125 ml. dry xylene is heated at 139°-141°C for 5 hours,cooled to room temperature, and suction-filtered to give 26.1 g, mp257°-259°C, of A/MA adduct. Solvent stripping of the filtrate andcrystallization of the residue from benzene gives another 3.5 g, mp258°-260°C, of A/MA adduct. The mother liquor is solvent stripped andthe excess maleic anhydride sublimed off at 60°-65°C/0.1-0.2mm. Thesemi-crystalline residue (11.4g) is taken-up in 50 ml. hot benzene, thesolution decanted from some insolubles (3.5 g, mp>300°C) and cooled togive another 1.3 g, mp 260°-262°C, of A/MA adduct. The filtrate isconcentrated in vacuo to give 6.2 g (44% theory) of crude monomer as apale orange liquid. IR and NMR analysis indicated the presence ofconsiderable anhydride-containing and other unknown impurities.

EXAMPLE XVII 1,3-Bis(hydroxymethyl)tetramethyldisiloxane Bis(2-Cyanoacrylate)

A mixture consisting of 125.4 g (0.400 mole) anthracene/2-cyanoacrylicacid adduct-K salt and 46.2 g (0.200 mole) 1,3-bis (chloromethyl)tetramethyldisiloxane in 340 ml. dry DMF is heated at 100°C for one hourand quenched in 3400 ml water. The gummy product is twice extracted into500 ml portions of benzene, and the combined extracts are washed with4×250 ml water, 1×250 ml saturated sodium chloride solution, and thendried over magnesium sulfate. The dried solution is concentrated toabout 400 ml and filtered slowly through a column of 500 g. alumina,neutral, activity I, at a fast dropwise rate and eluted further with anadditional 1000 ml benzene. Solvent stripping gives 98.9g (70% theory)of the bis-adduct as a colorless gum.

The NMR and IR spectra are consistent with the proposed structure. Someextraneous peaks due to impurities are seen in the NMR scan but not inthe IR spectrum.

In another rum using 1,3-bis (bromoethyl) tetramethyldisiloxane asreactant, the purity of the crude bis-adduct isolated via benzeneextraction is very similar to that obtained from the dichloro reactant.Chromatography on alumina, acid, activity I, affords a 64% recovery ofbis-adduct on elution with 1:1 benzene-hexane, benzene, 1:1benzene-chloroform and chloroform. Only a marginal improvement in purityis obtained for some fractions, and there is strong indication ofproduct degradation on the column.

A mixture consisting of 52.7 g (0.0743 mole) bis-anthraceneadduct/1,3-bis (hydroxymethyl) tetramethyldisiloxane bis(2-cyanoacrylate), 43.8 g (0.446 mole) maleic anhydride, 0.1 ghydroquinone, and 1.0 g phosphorus pentoxide in 190 ml. dry, SO₂-inhibited xylene is heated at a gentle reflux (140 °C) for 8 hours,cooled to room temperature, and filtered to give 30.6 g, mp 258°-262°C,of A/MA adduct. The filtrate is solvent stripped to a dark orange syrupwhich is taken-up in 50 ml. benzene and filtered to give an additional4.2 g, mp. 258°-261°C, of A/MA adduct. The resultant filtrate isconcentrated to a syrupy residue again and the excess maleic anhydrideis sublimed off at 65°-75°C/0.2mm. The pot contents are slurried in 25ml. benzene and filtered to afford 1.0 g, mp 235°-258° C. of A/MAadduct. The mother liquors are concentrated to about 50 ml. and dilutedwith about 25 ml. hexane to give, in two stages, an additional 0.3 g.and 0.2 g. of A/MA adduct. A final solvent stripping of the filtrategives 22.3 g (85% theory) of the bis (2-cyanoacrylate) monomer, abrown-orange syrupy liquid. The total A/MA adduct yield is 36.3 g(89theory).

IR and NMR assay confirmed the identity of the monomer but indicatedcontamination by some residual A/MA adduct and other unknownsilicone-containing impurities.

EXAMPLE XVII

In a manner analogous to the above examples, the following difunctionalmonomers are also prepared:

methylene glycol bis (2-cyanoacrylate) from methylene iodide;

1,3-butanediol bis (2-cyanoacrylate) from 1,3-dichlorobutane;

1,5-pentanediol bis (2-cyanoacrylate) from 1,5-dichloropentane;

1,6-hexanediol bis (2-cyanoacrylate) from 1,6-dichlorohexane;

1,6-hexanediol bis (2-cyanoacrylate) from 1,6-dibromohexane;

1,7-heptanediol bis (2-cyanoacrylate) from 1,7-dibromoheptane;

1,8-octanediol bis (2-cyanoacrylate) from 1,8-dibromooctane;

1,9-nonanediol bis (2-cyanoacrylate) from 1,9-dichlorononane;

1,10-decanediol bis (2-cyanoacrylate) from 1,10-dibromodecane;

1,12-dodecanediol bis (2-cyanoacrylate) from 1,12-diclorododecane;

1,12-dodecanediol bis (2-cyanoacrylate) from 1,12-dibromododecane,

2-butyne-1,4-diol bis (2-cyanoacrylate) from 2-butyne-1,4-diol;

neopentyl glycol bis (2-cyanoacrylate) from neopentyl glycol;

1,4-bis (hydroxymethyl) benzene bis (2-cyanoacrylate) from1,4-bis(chloromethyl) benzene; and

Bis(4-hydroxybutyl) ether bis (2-cyanoacrylate) from bis(4-hydroxybutyl) ether.

EXAMPLE XVIII Cyclopentadiene/IBC Adduct (Isobutyl2-Cyano-5-Norbornene-2-Carboxylate) (II)

To first prepare the cyclopentadiene monomer, dicyclopentadiene (95%,Enjay Chemical) is charged into a round bottom flask fitted with amagnetic bar stirrer, 30 cm. Vigreux column packed with Berl saddles,and a distillation head/receiver. The dimer is heated with stirring,under nitrogen and at atmospheric pressure, to reflux. After collectinga small forerun cut at bp 28°-36°C, the cyclopentadiene monomer iscollected at bp 36°-40°C in a Dry Ice cooled receiver. The monomer isused immediately in the following step.

Into a one-liter round bottom flask fitted with a thermometer,condenser, Drierite drying tube, dropping funnel, nitrogen inletadapter, and a magnetic bar stirrer is charged 92.2g (1.40 moles)cyclopentadiene monomer (freshly distilled), 500 ml dry benzene, and0.1g p-methoxyphenol. The solution is cooled with stirring to 5°C and tothis is added, over one hour and at 5°-15°C, 214g (1.40 moles) isobutyl2-cyanoacrylate (inhibited with excess SO₂). The exotherm subsidesquickly after the addition of isobutyl 2 -cyanoacrylate The ice bath isremoved and the solution stirred at room temperature overnight. Thesolution is solvent stripped to give 312.6g (102% theory) of crudeadduct, a colorless liquid. The latter is inhibited with 0.1gp-methoxyphenol and distilled in vacuo through a 6 inch Vigreux column.Pure isobutyl 2-cyano- 5-norbornene-2-carboxylate is collected at bp91°C (0.4mm) - 96°C (0.6mm). The yield of colorless distillate is 287.0g(94% theory).

Tlc: 1:1 c₆ h₆ /chcl₃, Rf 0.7; C₆ H₆, Rf 0.84 (all TLC procedures wereconducted on Eastman 6060 Silica Gel chromatogram sheets). On the basisof NMR, there is approximately a 60/40 ratio of the two expectedstereoisomers.

EXAMPLE XIX Cyclopentadiene/2-Cyanoacrylic Acid Adduct(2-Cyano-5-Norbornene-2-Carboxylic Acid) (III)

To a solution of 250 g (1.14 moles) isobutyl2-cyano-5-norbornene-2-carboxylate (IBC/CPD adduct) in 1000 ml. 95%ethanol is added a solution of 112 g (1.71 moles) of potassium hydroxide(86%w) in 1000 ml. water. The solution is refluxed on a steam bath forone hour, diluted with 3500 ml. water, and extracted with 2 × 400 ml.benzene to remove any unreacted ester. The aqueous phase is acidified topH 1 with 6 N HCl and the oily product extracted into 4 × 200 ml.chloroform. The combined extracts are backwashed with 3 × 200 ml. water(which removed the orange color), dried over anhydrous sodium sulfate,and solvent stripped to give 182.3g (98% theory) of the crude adduct, apale orange syrupy liquid. Crystallization from benzene/hexane givesthree crops of purified 2-cyano-5-norbornene-2-carboxylic acid: (1) 89.7g, mp 87.5°-92°C, (2) 34.2 g, mp 87.5°-96.5°C, and (3) 15.9 g, mp.85°-90°C.

A sample, mp 88°-96°C, from an earlier run showed spectralcharacteristics consistent with the proposed structure. The NMR spectrumshows that the ratio of stereoisomers is now 80/20 (vs 60/40 in theester precursor).

Neutralization Equiv. (mp 88°-96°C): Found, 163.9; Calcd, 163.2

EXAMPLE XX Cyclopentadiene/2-Cyanoacrylic Acid Adduct - Potassium Salt(Potassium 2-Cyano-5-Norbornene-2-Caroxylate) (Iv-A)

A stirred solution of 134.0 g (0.822 mole)2-cyano-5-norbornene-2-carboxylic acid in 400 ml. anhydrous methanol isadjusted from pH 1.5 to pH 9.0 (equivalence point) by the dropwiseaddition of a solution of 20% w/v potassium hydroxie in 95% ethanol. Thesolution is solvent stripped to a gum which is taken up several times inacetone and concentrated to a gummy residue each time. The gum, ontrituration with 1:1 acetone - benzene (900 ml), gives white solids.Filtration, washing with acetone, and air-drying gives 92.5 g ofproduct, mp 188°-189°C dec. Concentration of the filtrate to 400 mlgives another 19.9 g, mp. 188°C dec. Solvent stripping to a syrupyresidue and crystallization from acetone/hexane and acetone gives twomore crops of product; mp 22.6 g. mp. 188.0°-188.5°C dec. and 21.2 g,mp. 190°-191°C dec. The total yield of potassium 2-cyano-5-norbornene-2-carboxylate is 156.2 g (94% theory).

EXAMPLE XXI Bis-Cyclopentadiene Adduct/Ethylene GlycolBis(2-Cyanoacrylate); [Ethylene GlycolBis(2-Cyano-5-Norbornene-2-Carboxylate)]

A mixture of 40.3g (0.200 mole) potassium2-cyano-5-norbornene-2-carboxylate, 18.8g (0.100 mole)1,2-dibromoethane, and 118 ml. dry DMF is heated at 100°C for one hourand quenched in 1200 ml. water. The orange gum is extracted into 1 × 200ml. and 2 × 100 ml. chloroform, and the combined extracts are washedwith 4 × 100 ml. water, dried over a mixture of magnesium sulfate anddecolorizing carbon, filtered, and solvent stripped to an orange syrupyliquid (34.0g, 96%). The crude product is chromatographed on 200 galumina, neutral, activity I, and eluted with benzene (600 ml) to give23.9g (68% theory) of bis-adduct, a colorless syrupy liquid. The NMRspectra of the 34.0g and 23.9g fractions were essentially identical andconsistent with the proposed structure. The yield reduction is due toproduct degradation on the column.

EXAMPLE XXII Ethylene Glycol Bis (2-Cyanoacrylate) (EGBCA) viaBis-Cyclopentadiene Adduct/EGBCA (V)

A mixture consisting of 10.0g (0.0284 mole) bis-cyclopentadiene/ethyleneglycol bis (2-cyanoacrylate) adduct, 16.7g (0.170 mole) maleicanhydride, 0.1g hydroquinone, and 0.5g phosphorus pentoxide in 53 ml.dry xylene (SO₂ inhibited) is refluxed at 138°-142°C for seven hours andcooled to room temperature. A small amount of white solids (0.8g, mp243°-245°C), probably homopolymer, is collected via suction-filtration.The filtrate is solvent stripped to a yellow syrup from which theresidual xylene is removed by periodic additions of benzene and solventstripping. The excess maleic anhydride is sublimed off at70°-75°C/0.1mm. The residual syrup, which crystallized on cooling, wastaken-up in 75 ml. hot benzene, filtered from the insoluble gelatinouspolymer (0.8g), and concentrated to a yellow syrup (14.1g). The latteris triturated several times with hot hexane and benzne/hexane mixtures.The extracts give several crops of white needles on cooling to roomtemperature or below: 1.6 g. mp. 105°-122°C; 3.8g, mp. 74°-122°C; 0.5g,mp 86°-136°C; 0.2g, mp. 87°-136°C, 0.2g, mp. 119°-136°C. The residualnonextractable yellow syrup afforded 2.0g (32% theory) of EGBCA monomer,mp 96°-103°C (mixed up 100°-104°C), on crystallization from benzene inthe cold.

EXAMPLE XXIII Norbornadiene/Isobutyl 2-Cyanoacrylate Adduct (II);4-Carboisobutoxy-4-cyanotetracyclo[4.2.1.0²,9.0³,7 ] nonane.

Into a 100 ml. round bottom flask fitted with a condenser, thermometer,magnetic stirring bar, and a Drierite filled drying tube is charged 18.4g (0.200 mole) norbornadiene, 30.6 g (0.200 mole) isobutyl2-cyanoacrylate (inhibited with excess sulfur dioxide), and 0.1 ghydroquinone monomethyl ether (MEHQ). The solution is stirred and heatedunder a nitrogen atmosphere to 110°C. After 15 minutes at 100°C., thesolution became cloudy, more viscous, and the reflux rate diminished.The mixture is then heated to 150°C. and maintained at this temperaturefor 24 hours. The solution is cooled to room temperature, diluted with200 ml. hexane, filtered to remove polymeric solids, and the filtratesolvent stripped to a dark orange syrupy residue. The lattter isdissolved in 200 ml. acetone and to the resultant solution is added 800ml. of an aqueous solution containing 96 g. of potassium permanganateand 96 g. magnesium sulfate. After several minutes, the excess potassiumpermanganate is destroyed by bubbling sulfur dioxide gas into thesolution. The manganese dioxide precipitate is filtered and the solidswashed thoroughly with acetone. After dilution of the filtrate withone-half of its volume with water, the product is extracted intochloroform. The extract is backwashed with 3 × 500 ml. water, dried overanhydrous magnesium sulfate, filtered, and solvent stripped underreduced pressure to give 27.2 g (56% theory) of crude adduct.Distillation affords 24.0 g (49% theory) of the purenorbornadiene/isobutyl 2-cyanoacrylate adduct, b.p. 110°-112°C. (0.4mm), a colorless liquid.

EXAMPLE XXIV Norbornadiene/2-Cyanoacrylic Acid Adduct (III);4-Cyanotetracyclo [4.2.1.0²,9.0³,7 ]nonane-4-carboxylic acid.

Into a flask fitted with a condenser and magnetic stirring bar ischarged 12.3 g (0.05 mole) norbornadiene/isobutyl 2-cyanoacrylic acidadduct and a solution of 4.9 g 86% potassium hydroxide (0.075 mole) in75 ml. of water. After heating at reflux for 1.5 hours, the solution iscooled to room temperature and extracted with 2 × 25 ml. of hexane toremove any nonsaponified adduct. The aqueous phase is acidified to pH 2with 6 N hydrochloric acid and the liberated oily product is taken up in100 ml. ethyl acetate. The extract is filtered to remove some whiteinsoluble solids (0. 9g., m.p. 182°C.) and the filtrate washed with 3 ×25 ml. water, 1 × 25 ml. saturated sodium chloride solution, and solventstripped in vacuo to a pale yellow, viscous oil (8.7 g.).Crystallization of the oily product from benzene/hexane in the coldaffords 4.2 g of the norbornadiene/2-cyanoacrylic acid adduct, whitecyrstals, m.p. 83°-86°C. Another 3.0 g. of adduct, m.p. 81°-84°C., isobtained on concentration of the mother liquors and cooling. Thecombined crops of adduct are recrystallized from 1:2 benzene/hexane toafford 5.9 g of pure adduct, white crystals, m.p. 81°-83°C. Anal:Neutralization Equivalent: Found, 189.06 g/equiv.; Calculated (Theory),189.22 g/equiv.

EXAMPLE XXV

In a manner analogous to that of Example XXI, the difunctional monomersspecified in Example XVII are prepared from the corresponding bis(2-cyano-5-norbornene-2-carboxylic acid) esters of the diols.

Thus, having described the preparation of the bis esters of thisinvention, specific embodiments which utilize these bis esters will nowbe described.

In the broadest aspect, the individual difunctional bis(2-cyanoacrylate) monomers can be either homopolymerized orcopolymerized and employed as adhesives for joining or filling thevarious materials previously noted, or can be used as protectivecoatings on various materials, such as paper goods. Those difunctionalmonomers which are crystalline solids at room temperature requiredissolution in some solvent before they can advantageously be employedas an adhesive or coating material. Such a solvent may include acomonomer of this invention which is liquid at room temperature, such as1,3-bis (hydroxymethyl) tetramethyldisiloxane bis (2-cyanoacrylate);other monomers which act as a solvent for the bis (2-cyanoacrylate) andcan be copolymerized therewith; or if one or more of only the solid bis(2-cyanoacrylate) monomers are employed, a solvent such as the aromatichydrocarbons or other mutually miscible aprotic solvents. The use ofthese latter solvents is not an entirely desirable alternative, however,since such solvents do not polymerize or copolymerize but merely areentrapped in the polymerized material, thus not contributing to isdesirable properties.

In preferred embodiments the monomers of this invention are employed incomonomer compositions which comprise admixtures of the bis(2-cyanoacrylates) and at least one polymerizable monofunctional esterof 2-cyanoacrylic acid. Initiation and propagation of polymerization ofsuch compositions is accomplished by means of an anionic catalyst ashereinafter described or, alternatively, by thermal or other meansrecognized as being suitable for initiating the polymerization ofmonomers having the cyanoacrylate function present in their structure.

Desirable esters of 2-cyanoacrylic acid include alkyl esters of2-cyanoacrylic acid, wherein the alcoholic moiety of the ester is eitheran alkyl group of from 1-16 carbon atoms, a cyclohexyl group, or aphenyl group. The monofunctional 2-cyanoacrylate, being a liquid at roomtemperature, functions as a reactive comonomer and solvent for thedifunctional bis (2-cyanoacrylates). The bis (2-cyanoacrylate) monomeris an effective crosslinking agent when included in amounts as small as1% by weight based on the total weight of the monomers present.Generally, improvements in polymer properties such as breaking strengthare observed when higher concentrations of crosslinking difunctionalmonomers are included, up to and including the maximum amount soluble inthe monofunctional 2-cyanoacrylate ester.

In Table I, illustrative maximum solubilities of various difunctionalmonomers of this invention in isobutyl 2-cyanoacrylate are noted. Onceone has determined which difunctional monomer and which monofunctionalmonomer he desires to include in blend of these monomers, it is a simpletask to determine the maximum solubility of the difunctional monomer inthat specific ester of 2-cyanoacrylic acid. Less than the maximum amountsoluble can, of course, be employed, while still obtaining excellentcrosslinking with the ester of 2-cyanoacrylic acid and giving a polymerhaving improved adhesive properties.

                                      TABLE I                                     __________________________________________________________________________    Maximum Solubility of Bis (2-Cyanoacrylate) Monomers in                       Isobutyl 2-Cyanoacrylate at Room Temperature. -                                                        % By Weight(approx.)                                 __________________________________________________________________________    Ethylene glycol bis(2-cyanoacrylate)                                                                   5                                                    1,3-Propanediol bis (2-cyanoacrylate)                                                                  9                                                    1,4-Butanediol bis (2-cyanoacrylate)                                                                   15                                                   trans-2-Butene-1,4-diol bis (2-cyanoacrylate)                                                          7                                                    1,6-Hexanediol bis (2-cyanoacrylate)                                                                   34                                                   2,5-Hexanediol bis (2-cyanoacrylate)                                                                   25                                                   1,8-Octanediol bis (2-cyanoacrylate)                                                                   17                                                   1,9-Nonanediol bis (2-cyanoacrylate)                                                                   32                                                   1,10-Decanediol bis (2-cyanoacrylate)                                                                  7                                                    1,12-Dodecanediol bis (2-cyanoacrylate)                                                                6                                                    1,3-bis (Hydroxymethyl) tetramethyl-                                           disiloxane bis (2-cyanoacrylate)                                                                      ∞                                              __________________________________________________________________________

In order to initiate the polymerization reaction of either the monomersor the comonomer blends of this invention, it is suitable to use a basiccatalyst such as a metal hydroxide, a basic salt, ammonia, or organicamines. Other weak nucleophiles such as water and alcohol also caninitiate reaction. Polymerization by free radical and thermal means isalso possible, but anionic initiation is preferred and favored becauseof the presence of strong electron withdrawing groups in thecyanoacrylate monomer structure.

In general, those catalysts or initiators that are suitable for thepolymerization of esters of 2-cyanoacrylic acid, whether chemical innature or in the form of radiant energy, are suitable for initiating andpropagating polymerization of the monomers of this invention whether ashomopolymers, or copolymers from monomer blends thereof, or incombination with esters of 2-cyanoacrylic acid.

Preferred catalysts are the organic amines, especially tertiary amines;specific examples of which include N,N-dimethylaniline,N,N-diethylaniline, N-methylbenzylamine, triethanolamine, triethylamine,diethanolamine, diethylamine, 2-picoline, 4-picoline, tributylamine,4-ethylpyridine, pyridine, N,N-diethylethylenediamine,N,N-dimethyl-p-toluidine, N,N-diethyl-1-napthylamine, andhexamethylenediamine. Of these, N,N-dimethyl-p-toluidine is preferred.

Only a trace amount, e.g., 0.005% by weight of catalyst is necessary toinitiate polymerization. Yet, to evenly distribute such a trace amountthroughout a monomer, or comonomer blend, is rather difficult.Therefore, a convenient and preferred technique for catalysis of filledcyanoacrylate compositions is to incorporate the trace amounts of aminecatalyst required on the filler particles. On stirring a monomer/fillerblend, the catalyst diffuses from the filler particls into the compositemixture. The catalyzed composition proceeds through an initial inductionperiod, during which the mixture maintains a relatively constant workingviscosity. This is followed by a gellation stage which in turn israpidly followed by an almost instantaneous transition (in 5-15 seconds)to a hard composite mass.

Unfilled bis (2-cyanoacrylate) monomers, or their comonomer blends withother cyanoacrylates, are catalyzed by contacting the neat monomer witha very small amount of alumina which has been pretreated with a highconcentration of the amine catalyst, generally 4% by weight based on thealumina. The amine catalyst diffuses from the alumina particles into themonomer phase. The catalyzed monomer phase is separated from the verysmall amount of alumina catalyst particles by allowing them to settleout to the bottom of the mixing vessel, or even removed if desired,prior to gellation. The time required for the catalyzed monomer to reachthe gellation and polymerization stage can be varied by modifying themonomer/catalyst carrier contact time, weight ratio of monomer tocatalyst carrier, catalyst concentration on the alumina particles, andsulfur dioxide inhibitor level in the monomer.

In preparing compositions that are to be worked or shaped afterinitiating catalysts, such as those employed in dental applications, theperiod from the onset of mixing to the beginning of the gellation stage(gel time) is the time period during which the composition can beworked. After the gellation stage has begun, through to a period oftransition to a hard set material, the polymerizing material ought notbe disturbed. For pit and fissure sealant formulations gel times of 1-2minutes and transition times of 5-15 seconds are desirable. Specific geland transition periods can be obtained by decreasing and increasing theamounts of catalyst and the amount of monomer inhibitor, such as sulfurdioxide, or the balance between catalyst and inhibitor. The use ofsulfur dioxide inhibitors in 2-cyanoacrylate systems is well known andneed not be discussed here in detail.

The comonomer blends of this invention employing a monofunctionalmonomer consisting of an ester of 2-cyanoacrylic acid can be utilizedeither in filled or unfilld systems. When a filler is employed, it canbe any material resistant to the abrasion, erosion, or corrosive attackby substances that are likely to contact the polymerized filledmaterial. Such fillers can be powdered metal or metal oxides, silica orsilicacious materials, carbides, and the like. For dental applicationsthe preferred fillers are quartz and alumina. Other fillers such asglass and polyethylene may be used. For dental and other applicationsthe particle size should substantially be in the range of from 1 to 100microns. Larger particles are not deleterious, but do not provide asmooth textured material. Similarly, smaller particles are not desirablesince they are too small to serve as a good aggregate. The filler ifused should be employed in amounts sufficiently large to be of value,e.g., at least 10% by weight, and should not be used in so large aquantity, e.g., more than 85% by weight, that all the filler particlesare not wetted by the monomer or monomer blend. Generally, a desirablequantity of filler will be in the range of from 50% to 80% by weight.These percentages of filler are based on the total weight of monomersand filler present in the composition.

In Table II there is summarized the lap shear adhesion and the breakingstrength properties of various polymeric compositins prepared from bothfiller and unfilled blends compositions difunctional monomers andisobutyl 2-cyanoacrylate. Each blend was catalyzed withN,N-dimethyl-p-toluidine by the appropriate technique as heretoforediscussed.

The compositions set forth in Table II can be suitably employed as pitand fissure sealants. The patient's mouth is first rinsed with an oralantiseptic and then with water. The teeth are isolated with cottonrolls, thoroughly dried with an air syringe, and etched forapproximately one minute with phosphoric acid. The patient then rinseshis mouth thoroughly with water to remove the acid from the toothsurfaces. The teeth are again isolated with cotton rolls and againthoroughly dried. The pit and fissure sealant prepared according to theforegoing description is then applied by conventional techniques.

Breaking strengths are measured by compression testing on an Instrontester at a strain rate of 0.02 inches per minute. Cylindrical testspecimens, measuring 0.15 inch in diameter and 0.30 inch length, areprepared by pouring catalyzed monomer compositions into Teflon molds,allowing the mass to polymerize, extruding the specimens from the molds,polishing the ends flat and smooth, and conditioning the specimens inwater at 100°F for 24 hours prior to compression testing. Thestress/strain curve on compression consists of a brittle component and aviscoelastic type component which is evident beyond the yield point.Breaking strengths reported are calculated from the compressive forcevalues where the specimens undergo a physical breakdown, as determinedinstrumentally, and are invariably of greater magnitude than the yieldstrengths at the proportional limit.

Shear adhesion measurements were made on carefully cleaned steel plates(0.05 inch × 2 inches × 0.1 inch) cemented together to give a 0.5 × 0.5inch lap joint. A 37.5 gram weight was placed on top of the joinedsurfaces until a firm adhesive bond was established. The specimens wereconditioned at room temperature for 24 hrs. and the shear adhesive forcemeasured on an Instron tester at a strain rate of 0.5 inch per minute.

                                      TABLE II                                    __________________________________________________________________________    STRENGTH PROPERTIES OF FILLED AND UNFILLED CYANOACRYLATE POLYMER              COMPOSITIONS                                                                                % Monomer Content Based On                                                    Total Weight Monomers                                                                          Filler Content Based On                                                                           Breaking Strength                        Present In Composition                                                                         Weight Total Composition                                                                          PSI                        Difunctional Bis                                                                            Percent                                                                              Percent   Alumina                                                                              Quartz Lap Shear                        (2-Cyanoacrylate) of                                                                        Difunctional                                                                         Isobutyl-2-                                                                             Filler Filler Adhesion                         the Diol -    Monomer                                                                              (Cyanoacrylate)                                                                         % By Weight                                                                          % By Weight                                                                          PSI   Range  Average             __________________________________________________________________________       --         0      100       72-75  0      1370  5470-8220                                                                            6850                   --         0      100       0      80     --    6470-6960                                                                            6760                   --         0      100       0      0       660  5220-6840                                                                            6130                Ethylene glycol                                                                             4      96        75     0      1410  6520-7460                                                                            6860                Ethylene glycol                                                                             20     80        72     0      --    8000-8970                                                                            8380                Ethylene glycol                                                                             4      96        0      80     --    6880-7860                                                                            7410                Ethylene glycol                                                                             4      96        0      0      1150  4030-22920                                                                           7070                1,3-Propanediol                                                                             9      91        73.5   0      --    5540-7650                                                                            6560                1,3-Propanediol                                                                             9      91        0      0      1260  5230-7490                                                                            5840                1,4-Butanediol                                                                              15     85        72     0      --    8410-9350                                                                            8710                1,4-Butanediol                                                                              15     85        0      0      1160  5420-10600                                                                           7880                Trans-2-butene-1,4-diol                                                                     7      93        72     0      --    7840-8520                                                                            8130                Trans-2-butene-1,4-diol                                                                     7      93        0      0      1420  5870-7710                                                                            6460                2,5-Hexanediol                                                                              25.6   74.4      73.5   0      --    5790-7560                                                                            6710                2,5-Hexanediol                                                                              24     76        0      0      --    6540-10070                                                                           7720                1,6-Hexanediol                                                                              34     66        73.5   0      --    7050-8820                                                                            7950                1,6-Hexanediol                                                                              34     66        0      80     --    8560-9570                                                                            9120                1,6-Hexanediol                                                                              7      93        0      0      --    7550-37010                                                                           16280               1,6-Hexanediol                                                                              30     70        0      0       450  9810-12810                                                                           11460               1,6-Hexanediol                                                                              34     66        0      0      --    6630-16790                                                                           10540               1,8-Octanediol                                                                              17.6   82.4      73.5   0      --    6320-7070                                                                            6640                1,8-Octanediol                                                                              17     83        0      0      --    5750-10200                                                                           8270                1,9-Nonanediol                                                                              10     90        75     0      1700  7660-8460                                                                            8070                1,9-Nonanediol                                                                              33     67        73.5   0      --    4480-7610                                                                            5880                1,9-Nonanediol                                                                              8      92        0      0      1320  12340-21180                                                                          17760               1,9-Nonanediol                                                                              30     70        0      0       620  13300-22880                                                                          16740               1,10-Decanediol                                                                             7.5    92.5      73.5   0      --    5560-7330                                                                            6170                1,10-Decanediol                                                                             7.5    92.5      0      80     --    6880-7370                                                                            7070                1,10-Decanediol                                                                             7.5    92.5      0      0       880  5170-17460                                                                           10880               1,12-Dodecanediol                                                                           6.7    93.3      73.5   0      --    5100-6390                                                                            5700                1,12-Dodecanediol                                                                           6.5    93.5      0      0      1990  5100-7650                                                                            6850                1,3-bis (hydroxymethyl)                                                        tetramethyldisiloxane                                                                      50     50        73.4   0      --    2980-5820                                                                            4170                1,3-bis (hydroxymethyl)                                                        tetramethyldisiloxane                                                                      100    0         0      75     --    3400-5820                                                                            4610                1,3-bis (hydroxymethyl)                                                        tetramethyldisiloxane                                                                      100    0         0      0       300  11790-21390                                                                          >15870              __________________________________________________________________________

From Table III it can be observed that upon aging in water at an elvatedtemperature (100°F), the breaking strength of polymerized comonomerblends improves. Incidentally, these are the conditions of temperaturethat prevail in warm blooded animals' mouth, making these compositionsespecially suitable for dental applications.

                  TABLE III                                                       ______________________________________                                        Effect of Aging Time at 100°F in Water on Breaking Strength            Monomer:                                                                              Isobutyl-2-cyanoacrylate/Ethylene Glycol Bis (2-                              Cyanoacrylate) (EGBCA)                                                Filler: Alumina, 72% w                                                        Isobutyl-2-Cyanoacrylate/                                                                     Breaking Strength, psig (avg.)                                EGBCA (w/w) Monomer Mix                                                                       100°F/24 hrs.                                                                       100°F/7 days                              ______________________________________                                        100% IBC (Control)                                                                            6350         6870                                             99/1            6520         8140                                             98/2            6380         7790                                             96/4            7360         8700                                             94/6            7600         9300                                             90/10           8160         --                                               80/20           8380         --                                               ______________________________________                                    

Furthermore, it can be seen from Table IV that this increase in breakingstrength is not limited to polymerized comonomer blends of the monomersof this invention and isobutyl-2-cyanoacrylate, but extends to esters of2-cyanoacrylic acid generally.

                  TABLE IV                                                        ______________________________________                                        Effect of the Alkyl Group in Alkyl 2-Cyanoacrylate Monomers                   on Breaking Strengths of Crosslinked Alumina Filled                           Composites                                                                    ______________________________________                                        Crosslinking monomer:                                                                        Ethylene Glycol Bis (2-Cyanoacrylate)                                         (EGBCA)                                                        Filler:        72% w Alumina                                                               Breaking Strengths, psi                                          Alkyl Group of Alkyl Cyano-                                                                              Cyanoacrylate +                                    2-Cyanoacrylate Monomer                                                                      acrylate alone                                                                            3.6 mole % EGBCA                                   ______________________________________                                        Ethyl          7290        6060                                               Isobutyl       5470        7180                                               n-Amyl         2160        3070                                               i-Amyl         4590        5060                                               n-Hexyl         980        1450                                               n-Heptyl        390         670                                               ______________________________________                                    

EXAMPLE XXVI

Improvement in resistance to moisture of cyanoacrylate bonds through theinclusion of small amounts of biscyanoacrylate monomer in the monomermix used is illustrated.

Steel plates, 1/2 × 2 × 0.1 inches were freed of rust and cleaned bysuccessive immersion in dilute hydrochloric acid, water, dilute ammoniumhydroxide, water, and acetone.

Bonding was effected by addition of a small drop of cyanoacrylatemonomer on the end of one plate, followed by careful placement of theother plate to give a 1/2 × 1/2 inch lap joint. A 37.5 gram weight wasplaced on the lap joint until adhesive bonding took place. A set of 10specimens was prepared for shear adhesion testing under the conditionsshown in the accompanying Table. The abbreviation 100°F/H₂ O/1 dayindicates, for instance, that the specimen was kept immersed in water at100°F. for 1 day prior to the shear test.

The IBC (isobutyl 2-cyanoacrylate) monomer formulations were allcatalyzed with a trace amount of N,N-dimethyl-p-toluidine catalyst inorder to effect an adhesive bond within two minutes. The MCA (methylcyanoacrylate), a commercial adhesive (Loctite* Quick-Set Adhesive 404;Loctite Corp.), and its blend with the crosslinking monomer,1,8-octanediol bis(2-cyanoacrylate), formed an almost instantaneous bondand did not require addition of a catalyst.

All crosslinkable cyanoacrylate formulations were based on a 90% alkyl2-cyanoacrylate and a 10% w 1,8-octanediol bis(2-cyanoacrylate)(1,8-ODBCA) blend.

Shear adhesion testing was done on an Instron tester at a pull-rate of0.5 inches/minute. The values shown in the Table are averages of 10specimen measurements.

Based on the tabulated data, the following conclusions can be reached.

While MCA gave higher initial bond strengths than the IBC, the shearadhesive bond strength of the former deteriorated to about 30% of theinitial bond strength after 7 days in water at 100°F. The IBC and thecrosslinked IBC bonded specimens were not affected under the sameconditions. The crosslinked IBC bond strength was at least 20% greaterthan that obtained with IBC alone. Incorporation of the crosslinkingmonomer into MCA did not appear to improve the initial bond strength butgave an adhesive bond which was much more resistant to degradation inwater, comparing for example the 7 day drop from 2612 to 780 psi for MCAvs the 2000 to 1156 psi for the crosslinked MCA. After 7 days in water,the crosslinked MCA bond strength (1156 psi) was about 48% greater thanthat of the non-crosslinked MCA (780 psi).

                                      TABLE                                       __________________________________________________________________________    SHEAR ADHESIVE BOND STRENGTHS OF                                              CROSSLINKED VS NON-CROSSLINKED IBC AND MCA                                              Shear Adhesive Bond Strength, in psi                                __________________________________________________________________________                  90/10        90/10                                              Conditioned at                                                                          IBC IBC/1,8-ODBCA                                                                          MCA MCA/1,8-ODBCA                                      __________________________________________________________________________    100°F/air/1 day                                                                  508 612      2612                                                                              2000                                               100°F/H.sub.2 O/1 day                                                            512 812      1660                                                                              1476                                               100°F/H.sub.2 O/7 days                                                           524 628       780                                                                              1156                                               __________________________________________________________________________

From the foregoing description, it is apparent that the objects of thisinvention have been achieved in a new and novel manner. While onlyspecific embodiments have been illustrated, it should be apparent fromthe foregoing description to those skilled in the art that otheralternatives can be practiced within the spirit and the scope of thepresent invention.

What is claimed is:
 1. In the preparation of bis (2-cyanoacrylate)monomer represented by the General Formula VI ##EQU10## from2-cyanoacrylic acid ester of the General Formula I ##EQU11## the stepscomprising: a. introducing a blocking group by means of a Diels-Alderreaction in which a cyclic 1,3-diene is reacted with said cyanoacrylicester of Formula I to give a compound of the General Formula II##EQU12## b. converting said compound of General Formula II byhydrolysis to a compound represented by Formula III ##EQU13## convertingthe compound of Formula III to an acyl halide represented by the GeneralFormula IV(B): ##EQU14## c. coupling two acyl groups of compounds ofFormula IV(B) to each other through an -- O -- R -- O -- linkage byesterification with a difunctional alcohol to form a compoundrepresented by the General Formula V ##EQU15## d. and then heating thecompound of Formula V with maleic anhydride to displace said blockinggroups and form said bis (2-cyanoacrylate) of Formula VI; wherein saidblocking group ##SPC18##of Formula II, III, and V is any one of thegroup consisting of ##SPC19## where R₁ and R₂ are the same R₁ and R₂ areselected from the group consisting of H, an alkyl group of 1 to 5carbons, phenyl, Br or Cl and where R₁ and R₂ are different, R₁ is H andR₂ is a member selected from any of the group consisting of an alkylgroup of 1 to 5 carbons, phenyl, Br and Cl; ##SPC20## where R₃ is H orCH₃ ; and ##SPC21## wherein the organo linking group R of Formulas VIand V is the same and is any one of the group consisting of:

    --(CH.sub.2).sub.m --,

where m is an integer of from 1 to 20 inclusive; ##EQU16## where n is aninteger of from 0 to 18 inclusive, and R₄ and R₅ are independentlyhydrogen or a C₁ to C₅ alkyl group, R₄ and R₅ not simultaneously beinghydrogen;

    --(CH.sub.2).sub.r --Z--(CH.sub.2).sub.s --,

where Z is --O--, --S--, --CH=CH--; --C.tbd.C--; ##EQU17## and ##SPC22##where r and s are independent integers of from 1 to 10 inclusive and rand s total from 2 to 20, R₆ and R₇ are independently hydrogen or astraight or branched chain C₁ and C₅ alkyl group ##SPC23## where x and yare integers of from 1 to 6 inclusive; ##SPC24##where x and y are ashereinbefore defined;

    --CH.sub.2 --(CF.sub.2).sub.z --CH.sub.2 --,

where z is an integer of from 1 to 10 inclusive; and ##EQU18## andwherein R' of Formula I and II is an alcohol moiety selected from C₁ toC₁₆ alkyl, cyclohexyl or phenyl.
 2. A method according to claim 1 inwhich the cyclic 1,3 diene is selected from the group consisting ofanthracene, 9-methylanthracene, 9-bromoanthracene, 9-phenylanthracene,9,10-dimethylanthracene, 9,10-dibromoanthracene,9,10-diphenylanthracene, cyclopentadiene, methylcyclopentadiene, andnorbornadiene.
 3. A method according to claim 2 in which the diene iscyclopentadiene.
 4. A method according to claim 1 where the difunctionalalcohol is of the formulaHo[r"].sub. t OH where when t is = to or > 1,R" is propylene, and when t is > 2, R" is propylene, tetramethylene andethylene, and t is a range average such that the molecular weight isfrom about 76 to about
 2000. 5. A method according to claim 1 whereinfrom 25 to 200 mole percent excess of maleic anhydride is employed.
 6. Amethod according to claim 1 where the cyanoacrylic ester is isobutyl2-cyanoacrylate.
 7. A method according to claim 1 in which the diene isanthracene.
 8. A method according to claim 1 wherein the glycol isHO--(CH₂)_(m) --OH, where m is an integer of from 1 to 20 inclusive. 9.A method according to claim 1 in which the difunctional alcohol isselected from the group consisting ofHo--(ch₂)_(m) --OH where m is aninteger of from 1 to 20 inclusive; ##EQU19## where n is an integer offrom 0 to 18 and R₄ and R₅ are independently selected from the groupconsisting of hydrogen and C₁ to C₅ alkyl, but R₄, and R₅ notsimultaneously being hydrogen; Ho--(ch₂)_(r) --Z--(CH₂)_(s) --OH where Zis --O--, --S--, --CH=CH--, --C.tbd.C--, ##EQU20## and ##SPC25## where rand s are independent integers of from 1 to 10 inclusive and r and stotal from 2 to 20, R₆ and R₇ being as heretofore defined; ##SPC26##where x and y are integers of from 1 to 6 inclusive; ##SPC27## where xand y are as hereinbefore defined; Ho--ch₂ --(cf₂)_(z) --CH₂ --OH wherez is an integer of from 1 to 10 inclusive; and Ho--ch₂ --si(CH₃)₂--O--Si(CH₃)₂ --CH₂ --OH.
 10. In the preparation of bis(2-cyanoacrylate) monomer represented by the General Formula VI##EQU21## from 2-cyanoacrylic acid ester of the General Formula I##EQU22## the steps comprising: a. introducing a blocking group D bymeans of a Diels-Alder reaction in which a cyclic 1,3-diene is reactedwith said cyanoacrylic ester of Formula I to give a compound of theGeneral Formula II ##EQU23## b. converting said compound of GeneralFormula II by hydrolysis to a compound represented by Formula III##EQU24## neutralizing the compound of Formula III with a metal base ofwhich the designation M is the metal to form a metal salt compound ofthe General Formula IV(A): ##EQU25## c. coupling two carboxyl groups ofcompounds of Formula IV(A) to each other through an organo-linkinggroup - R - by ester formation through reaction with a dihalide to forma compound represented by the General Formula V ##EQU26## and thenheating the compound of Formula V with maleic anhydride to displace saidblocking groups and form said bis (2-cyanoacrylate) of Formula VI;wherein said blocking group ##SPC28##of Formula II, III, IV(A) and V isany one of the group consisting of ##SPC29## where R₁ and R₂ are thesame, R₁ and R₂ are selected from the group consisting of H, an alkylgroup of 1 to 5 carbons, phenyl, Br or Cl and where R₁ and R₂ aredifferent, R₁ is H and R₂ is a member selected from any of the groupconsisting of an alkyl group of 1 to 5 carbons, phenyl, Br and Cl;##SPC30## where R₃ is H or CH.sub. 3 ; and ##SPC31## wherein the organolinking group R of Formulas VI and V is the same and is any one of thegroup consisting of:

    --(CH.sub.2).sub.m --,

where m is an integer of from 1 to 20 inclusive; ##EQU27## where n is aninteger of from 0 to 18 inclusive, and R₄ and R₅ are independentlyhydrogen or a C₁ to C₅ alkyl group, R₄ and R₅ not simultaneously beinghydrogen;

    --(CH.sub.2).sub.r --Z--(CH.sub.2).sub.s --,

where Z is --O--, --S--, --CH=CH--;--C.tbd.C--; ##EQU28## and ##SPC32##where r and s are independent integers of from 1 to 10 inclusive and rand s total from 2 to 20, R₆ and R₇ are independently hydrogen or astraight or branched chain C₁ to C₅ alkyl group ##SPC33## where x and yare integers of from 1 to 6 inclusive; ##SPC34## where x and y are ashereinbefore defined;

    --CH.sub.2 --(CF.sub.2).sub.z --CH.sub.2 --,

where z is an integer of from 1 to 10 inclusive; and ##EQU29## andwherein R' of Formula I and II is an alcohol moiety selected from C₁ toC₁₆ alkyl, cyclohexyl or phenyl.
 11. A method according to claim 10 inwhich the dihalide is selected from the group consisting ofX--(ch₂)_(m)--X, where m is an integer of from 1 to 20 inclusive; ##EQU30## where nis an integer of from 0 to 18 and R₄ and R₅ are independently selectedfrom the group consisting of hydrogen and C₁ to C₅ alkyl, but R₄, and R₅not simultaneously being hydrogen; X--(ch₂)_(r) --Z--(CH₂)_(s) --X,where Z is --O--, --S--, --CH=CH--, --C.tbd.C--, ##EQU31## and ##SPC35##where r and s are independent integers of from 1 to 10 inclusive and rand s total from 2 to 20, R₆ and R₇ are independently hydrogen or astraight or branched chain C₁ to C₅ alkyl group ##SPC36## where x and yare integers of from 1 to 6 inclusive; ##SPC37## where x and y are ashereinbefore defined; X--ch₂ --(cf₂)_(z) --CH₂ --X, where z is aninteger of from 1 to 10 inclusive; and X--ch₂ --si(CH₃)₂ --O--Si(CH₃)₂--CH₂ --X; and X is either independently selected from the halogenschlorine, bromine, and iodine.
 12. A method according to claim 11wherein the dihalide is X--(CH₂)_(m) --X, where m is an integer of from1 to 20 inclusive.
 13. A method according to claim 10 in which thecyclic 1,3 diene is selected from the group consisting of anthracene,9-methylanthracene, 9-bromoanthracene, 9-phenylanthracene,9,10-dimethylanthracene, 9,10-dibromoanthracene,9,10-diphenylanthracene, cyclopentadiene, methylcyclopentadiene, andnorbornadiene.
 14. A method according to claim 13 in which the diene iscyclopentadiene.
 15. A method according to claim 10 wherein from 25 to200 mole percent excess of maleic anhydride is employed.
 16. A methodaccording to claim 10 where the cyanoacrylic ester is isobutyl2-cyanoacrylate.
 17. A method according to claim 10 in which the dieneis anthracene.